The study also found that setting goals and good interpersonal relationships are key components to healthy aging and increased lifespan.

All Age Groups Benefit

"Our finding that a strong sense of purpose is associated with healthy aging among individuals at all points in adult life demonstrates the importance of psychological traits in the aging process," says the study's co-author Nicholas Turiano, of the University of Rochester Medical Center, lead researcher along with Patrick Hill from Carleton University in Canada.

"Having a strong sense of purpose in the 30s was equally important as strong purpose for someone in their 70s," Turiano says.

The goals people set can be about anything from establishing retirement objectives to planning to take courses and going back to school — as long as they matter to the person setting them.

"They can be whatever individuals experience as purposeful,” Turiano says.

There’s a lot of variation in what people do that influences the aging process — and no set recipe for how to age successfully.

What doesn’t work: "Being passive, not setting goals and feeling like there is nothing important left to do in life is certainly not going to lead to positive things," Turiano says. "Planning for the future, taking action and considering how one's actions today may impact the future is most certainly going to lead to better aging outcomes."

Zeroing In On Purpose

For their study, Turiano and Hill evaluated data from more than 6,000 men and women between the ages of 20 and 75 enrolled in the nationwide Midlife in the United States study.

They particularly focused on analyzing questions related to purpose in life and interpersonal relations.

Scores were based on people rating themselves against three statements: "Some people wander aimlessly through life, but I am not one of them," "I live life one day at a time and don't really think about the future" and "I sometimes feel as if I've done all there is to do in life."

During a 14-year follow-up period, the 596 participants (9 percent) who died reported a lower sense of purpose in their lives and fewer positive relationships with others than those who survived.

Aging Doesn’t Start at 65

It's not surprising that a sense of purpose is key for older persons who are typically dealing with loss, retirement and a sense of no longer being active and useful to society. But the Hill/Turiano study documented the same longevity value in younger and middle-aged adults.

"Our findings provide the evidence that developing a stronger purpose in life at earlier ages has just as much benefit as it does for much older individuals at the end of their life span," says Turiano.

These results contribute to the ever-growing pool of knowledge about healthy aging.

Turiano says studying individuals much earlier in life is increasingly important as researchers recognize that aging processes do not start after age 65.

"Since the foundation for disease and disability are often initiated much earlier in life, we wanted to examine how developing a purpose in life protected individuals from earlier mortality across a wide age range," he says.

Jeanne Dorin is a Los Angeles-based writer who often covers health and wellness.